Occult malignancy in patients with venous thromboembolism: risk indicators and a diagnostic screening strategy.

BACKGROUND: The study was designed to analyse the risk indicators for a possible underlying malignancy and to evaluate whether extensive cancer screening is necessary in all patients with venous thromboembolism or not.
METHODS: In total, 126 patients with idiopathic deep venous thrombosis, and 121 patients with secondary deep venous thrombosis of lower extremity and without a known malignancy were studied. A diagnostic screening workup including a clinical history, physical examination, complete blood count, blood sedimentation rate, basic biochemistry panel including hepatic and renal function tests, prostate-specific antigen, a chest X-ray and an abdominopelvic ultrasonography was performed for all patients.
RESULTS: Suspicious findings suggesting an underlying cancer, previous history of venous thromboembolism, bilateral venous thrombosis and associated thrombosis in unusual sites were significantly more common in patients with idiopathic venous thrombosis. A malignancy was detected in 10 of the 126 patients (7.9%) without a known risk factor for deep venous thrombosis. During the follow-up period, a diagnosis of malignancy was established in two patients in the same group.
CONCLUSION: The risk of an underlying malignancy in patients with idiopathic venous thromboembolism is significantly higher. A moderate screening strategy has the capacity to identify the majority of the malignancies in such patients. We advocate simple laboratory tests, a chest X-ray and an abdominopelvic ultrasonography in order to search for an occult malignancy. A more extensive screening strategy may be considered for patients with suspicious findings for cancer, recurrent or bilateral venous thromboembolism and associated thrombosis in unusual sites.